Recurrent chronic subdural hematoma caused by active middle meningeal artery bleeding: A case report and review of hybrid embolization techniques.

Background: Middle meningeal artery embolization (MMAE) has emerged as a promising adjunct or alternative to surgical evacuation in the management of recurrent chronic subdural hematoma (CSDH). By targeting the vascular supply to the neomembrane, MMAE disrupts the pathological cycle of angiogenesis and microhemorrhage that underlies recurrence. However, direct angiographic evidence of active MMA bleeding into the subdural space remains exceedingly rare, and optimal embolization strategies in such settings are not well established. Case Description: We report a case of a 57-year-old man with recurrent postsurgical CSDH and new neurological deficits. Digital subtraction angiography revealed active contrast extravasation from a distal MMA branch into the subdural drain, suggesting ongoing arterial bleeding. A hybrid embolization approach was performed using a coil to scaffold the site of leakage, followed by Onyx injection to achieve definitive devascularization. Additional embolization of the contralateral MMA was also performed. The patient recovered without complications, and follow-up imaging confirmed near-complete resolution without recurrence. Conclusion: This case illustrates a rare angiographic finding of active MMA bleeding and supports the use of coil-assisted liquid embolization in technically complex or high-flow situations. A review of current embolization strategies and their pathophysiologic rationale is presented to guide management in similar cases.